chromium/third_party/blink/web_tests/external/wpt/css/css-sizing/dynamic-change-inline-size-003.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Test: Dynamic change to the inline-size of body</title>
<link rel="author" title="Ting-Yu Lin" href="mailto:[email protected]">
<link rel="author" title="Mozilla" href="https://www.mozilla.org/">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1731653">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1729122">
<link rel="stylesheet" href="/fonts/ahem.css">
<link rel="match" href="dynamic-change-inline-size-003-ref.html">
<meta name="assert" content="This test verifies that the dynamic change to body's inline-size triggers the reflow of its children.">

<style>
.abs {
  position: absolute;
  background: green;
  inline-size: 100px;
  padding-top: 100px;
}
.layout {
  font: 50px/1 Ahem;
  color: red;
  background-color: red;
  width: 100px;
  padding-top: 25%; /* This resolves against body's inline-size. */
}
</style>

<body>
  <!-- Test passes if there is a filled green square and no red. -->
  <div class="abs"></div>
  <div class="layout">XX</div>
</body>

<script>
/* Make sure the layout is up-to-date, which is essential to trigger the bug. */
document.documentElement.offsetHeight;

/* Change body's inline-size to trigger incremental reflow. */
document.body.style.inlineSize = "200px";
</script>